temporary closure plug

Abstract

The application provides a temporary sealing plug, which comprises a center tube, a first key body arranged on the inner wall of the center tube, a setting mechanism mounted outside the center tube and used for setting, a plug body mounted in the center tube and used for plugging a flow channel in the center tube, a second key body arranged on the plug body and capable of abutting on the first key body to prevent the plug body from moving downward, a guide mechanism provided with a guide structure and capable of rotating under the guidance of the guide structure when the plug body moves upward relative to the guide mechanism, and an elastic body mounted on the center tube and used for applying an upward force to the plug body. The application can solve the technical problem that the oil and gas flow conductivity of a fracture mouth is reduced due to over displacement in the process of segmented fracturing of a horizontal well, and improve the fracturing effect.

Description

Technical Field

[0001] This invention relates to the technical field of downhole tools for oil and gas drilling and fracturing, and particularly to a temporary plug. Background Technology

[0002] The development of unconventional oil and gas resources such as shale oil and gas, tight oil and gas, and deep coalbed methane has gradually become mainstream. However, due to the small porosity and low permeability of unconventional reservoirs, large-scale multi-stage fracturing is required to achieve better recovery rates. Currently, the commonly used large-scale fracturing method is the staged fracturing technology of pump-driven bridge plug-cluster perforation. This involves connecting the perforating gun, setting tool, and bridge plug in series and simultaneously lowering them downhole to the target formation. After setting the bridge plug and perforating the formation, the tool series is brought up to the wellhead. Soluble balls are then inserted at the wellhead to temporarily seal the wellbore, and fracturing begins. After the fracturing operation is completed, the above operation is repeated to achieve multi-stage fracturing.

[0003] However, during fracturing operations, after a section of the wellbore is temporarily sealed and fracturing is completed, the interval between the two fracturing sections is often short. The bridge plugs or packers set during the previous section, and the deployed plugging balls, may not deactivate in time. This causes the fluid pumped in the next section to enter the already fractured fractures and formation through the casing channels of the previous section, resulting in over-displacement. Over-displacement pushes the proppant around the fractured section further into the fracture, causing a pressure drop and potentially leading to partial closure of the fractures near the wellbore, creating a "dumpling-like" phenomenon. This reduces the oil and gas conductivity at the fracture opening, thus lowering the productivity of the fracturing well. Therefore, there is an urgent need to design a temporary sealing plug that can temporarily seal the wellbore, ensuring the normal progress of fracturing operations, while reducing formation damage caused by over-displacement and improving operational efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a temporary plug to solve the technical problem of reduced oil and gas conductivity at the fracture opening due to over-displacement during horizontal well fracturing operations, thereby improving the fracturing effect.

[0005] The above-mentioned objectives of the present invention can be achieved by the following technical solutions:

[0006] This invention provides a temporary occluder, comprising:

[0007] The central tube has a first key body on its inner wall;

[0008] A setting mechanism, which is installed outside the central tube, is used to achieve setting;

[0009] A plug is installed inside the central tube. The plug is used to block the flow channel inside the central tube. The plug is provided with a second key body. The second key body can abut against the first key body to prevent the plug from moving downward.

[0010] A guiding mechanism is provided with a guiding structure, and the blocking body can rotate under the guiding action of the guiding structure when it moves upward relative to the guiding mechanism;

[0011] An elastomer, which is mounted on the central tube, is used to apply an upward force to the blockage body.

[0012] In a preferred embodiment, the guide structure includes a first guide ramp, and the blockage body is provided with a second guide ramp that cooperates with the first guide ramp.

[0013] In a preferred embodiment, the guide structure includes a guide cylinder sleeved outside the blockage body; a limiting ring is provided on the inner side of the guide cylinder, and a first guide inclined surface is provided on the lower side of the limiting ring; a second guide inclined surface is provided on the upper side of the second key body, and the limiting ring is provided above the second key body and can limit the second key body to the lower side of the limiting ring.

[0014] In a preferred embodiment, the guide cylinder and the blocking body are connected by a shear pin.

[0015] In a preferred embodiment, the temporary sealing plug includes a fixing mechanism, which is disposed inside the central tube and abuts against the upper end of the guide cylinder, and the fixing mechanism is threadedly connected to the central tube.

[0016] In a preferred embodiment, the fixing mechanism includes a fixing cylinder, which is sleeved on the blockage body, and the outer wall of the fixing cylinder is threadedly connected to the inner wall of the central tube.

[0017] In a preferred embodiment, the central tube includes an upper tube section and a lower tube section, and the sealing mechanism is installed on the upper tube section; the upper part of the first key body is disposed on the upper tube section; the plug body can rotate under the guidance of the guide structure until the first key body and the second key body are misaligned, and the plug body can continue to move downward until it abuts against the lower tube section.

[0018] In a preferred embodiment, the outer diameter of the lower pipe section is smaller than the outer diameter of the upper pipe section; and / or, the outer wall of the lower pipe section is provided with an annular groove.

[0019] In a preferred embodiment, the inner wall of the central tube is provided with a plurality of circumferentially distributed guide grooves, and a first key body is formed between adjacent guide grooves. The upper end of the guide groove extends to the upper tube section, and the lower end of the guide groove extends to the lower tube section.

[0020] In a preferred embodiment, the sealing mechanism includes an expansion mechanism, an anchoring mechanism, and a sealing mechanism. The outer wall of the expansion mechanism is provided with a conical surface. The anchoring mechanism can move upward relative to the expansion mechanism and can expand outward under the action of the conical surface of the expansion mechanism during the relative upward movement. The sealing mechanism can move upward relative to the expansion mechanism and can expand outward under the action of the conical surface of the expansion mechanism during the relative upward movement.

[0021] The features and advantages of this invention are:

[0022] After the temporary plug is inserted into the well, the setting mechanism sets it. During the fracturing operation, the second key body abuts against the first key body to prevent the plug from moving downward, thus keeping the plug in the central tube and blocking the flow channel inside the central tube. Fracturing can be carried out without the need for ball dropping, effectively avoiding the risk of ball dropping hitting the pressure.

[0023] After fracturing is completed, the elastomer drives the plugging body to move upward relative to the guide mechanism, causing the plugging body to rotate under the action of the guide structure. This causes the second key on the plugging body to be misaligned with the first key, allowing the plugging body to avoid the first key and move downward. The plugging body leaves the central tube, opening the flow channel inside the central tube. This effectively avoids the risk of sand particles in the fractured area being transported to the formation depth due to wellbore blockage during the next stage of fracturing tool insertion and pumping. It significantly reduces the occurrence of over-displacement, helps ensure the oil and gas conductivity of the fracture opening, reduces the risk and production cost of fracturing operations, and facilitates rapid well commissioning and production after fracturing of unconventional oil and gas wells, shortening the construction cycle and improving the fracturing operation effect. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A half-sectional view of the overall structure of the temporary sealing plug provided by the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of the plug in the temporary sealing plug provided by the present invention;

[0027] Figure 3 A schematic diagram of the guide cylinder in the temporary sealing plug provided by the present invention;

[0028] Figure 4 for Figure 3 The cross-sectional view of the guide tube shown;

[0029] Figure 5 for Figure 3 The bottom view of the guide tube shown;

[0030] Figure 6 This is a schematic diagram of the structure of the central tube in the temporary sealing plug provided by the present invention;

[0031] Figure 7 This is a schematic diagram of the structure of the fixing cylinder in the temporary sealing plug provided by the present invention;

[0032] Figure 8 A schematic diagram of the anchoring mechanism in the temporary sealing plug provided by the present invention;

[0033] Figure 9 A top view of the plugging body and central tube before temporary plugging fracturing operation provided by the present invention;

[0034] Figure 10 A top view of the plugging body and central tube after temporary plug fracturing operation provided by the present invention;

[0035] Figure 11 A schematic diagram of the state of the high-elasticity rubber ball, guide cylinder, plugging body and central tube in the temporary sealing plug provided by the present invention before fracturing;

[0036] Figure 12 A schematic diagram of the state of the high-elasticity rubber ball, guide cylinder, plug body and central tube in the temporary sealing plug provided by the present invention during fracturing;

[0037] Figure 13 A schematic diagram showing the state of the high-elasticity rubber ball, guide cylinder, plugging body, and central tube in the temporary sealing plug provided by the present invention after fracturing;

[0038] Figure 14 This is a schematic diagram illustrating the function of the plug and the guide mechanism when the high-elasticity rubber ball in the temporary sealing plug rebounds, as provided by the present invention.

[0039] Explanation of icon numbers:

[0040] 1. Central pipe; 101. Upper pipe section; 102. Lower pipe section; 103. Annular groove;

[0041] 11. First key body; 12. Guide groove;

[0042] 3. Fixing mechanism; 31. Fixing cylinder; 32. Cylinder top groove;

[0043] 4. Blocking body; 41. Second guide ramp; 42. Second key body;

[0044] 5. O-ring seal;

[0045] 7. Guiding mechanism; 71. Guide cylinder; 72. Limiting ring;

[0046] 73. Guide structure; 74. First guide ramp;

[0047] 9. Cut the pin;

[0048] 90. Elastomer; 91. High-elasticity rubber ball;

[0049] 80. Sealing mechanism;

[0050] 2. Expansion mechanism; 21. Conical surface;

[0051] 6. Sealing mechanism;

[0052] 8. Anchoring mechanism; 81. Kawa;

[0053] 61. Locking mechanism. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] This invention provides a temporary occluder, such as Figures 1-13 As shown, it includes: a central tube 1, a setting mechanism 80, a plugging body 4, a guiding mechanism 7, and an elastic body 90. The setting mechanism 80 is installed outside the central tube 1 and is used to achieve setting. A first key body 11 is provided on the inner wall of the central tube 1. The plugging body 4 is installed inside the central tube 1 and is used to block the flow channel inside the central tube 1. The plugging body 4 is provided with a second key body 42, which can abut against the first key body 11 to prevent the plugging body 4 from moving downward. The guiding mechanism 7 is provided with a guiding structure 73. When the plugging body 4 moves upward relative to the guiding mechanism 7, it can rotate under the guidance of the guiding structure 73. The elastic body 90 is installed in the central tube 1 and is used to apply an upward force to the plugging body 4.

[0056] After entering the well, the setting mechanism 80 sets the seal. During the fracturing operation, the second key body 42 abuts against the first key body 11 to prevent the plugging body 4 from moving downward, so that the plugging body 4 stays in the central tube 1 and blocks the flow channel in the central tube 1. Fracturing can be carried out without the need for ball dropping, effectively avoiding the risk of ball dropping hitting the pressure.

[0057] After fracturing is completed, the elastomer 90 drives the plugging body 4 to move upward relative to the guide mechanism 7, causing the plugging body 4 to rotate under the action of the guide structure 73. This causes the second key body 42 on the plugging body 4 to be misaligned with the first key body 11, allowing the plugging body 4 to avoid the first key body 11 and move downward. The plugging body 4 leaves the central tube 1, and the flow channel in the central tube 1 opens. This effectively avoids the risk of sand particles in the fractured area being transported to the formation depth due to wellbore blockage during the next stage of fracturing tool insertion and pumping. It significantly reduces the occurrence of over-displacement, helps to ensure the oil and gas conductivity of the fracture opening, reduces the risk and production cost of fracturing operations, and helps to ensure rapid well commissioning and production after fracturing of unconventional oil and gas wells, shortens the construction cycle, and improves the fracturing operation effect.

[0058] In one embodiment, the central pipe 1 includes an upper pipe section 101 and a lower pipe section 102, such as Figure 1 and Figure 6 As shown, the setting mechanism 80 is installed on the upper pipe section 101; the upper part of the first key body 11 is disposed on the upper pipe section 101; the blocking body 4 can rotate under the guidance of the guide structure 73 until the first key body 11 and the second key body 42 are misaligned, and the blocking body 4 can continue to move downward until it abuts against the lower pipe section 102. When the second key 42 abuts against the upper end of the first key 11, the pressure is transmitted through the first key 11 to the entire upper pipe section 101. The central pipe 1 transmits the pressure to the setting mechanism 80. The overall structural strength of the central pipe 1 is sufficient to support the normal operation of the fracturing operation. After the second key 42 is offset from the first key 11, the wellhead discharge rate is increased, the bottom hole pressure rises, and the plugging body 4 overcomes the elastic force of the elastic body 90 under the action of pressure and slides into the lower pipe section 102, where the lower pipe section 102 bears the pressure. The wellhead discharge rate continues to increase until the connection between the lower pipe section 102 and the upper pipe section 101 is sheared, and the lower pipe section 102 and the plugging body 4 slide down to the bottom of the well together, forming a borehole.

[0059] Furthermore, since the outer diameter of the lower pipe section 102 is smaller than that of the upper pipe section 101, the plug 4 transmits pressure to the lower pipe section 102, making it easier for the lower pipe section 102 to be sheared.

[0060] Furthermore, the outer wall of the lower pipe section 102 is provided with an annular groove 103. The pressure bearing capacity of the annular groove 103 is relatively weak, which makes it easier for the lower pipe section 102 to be sheared by force.

[0061] Preferably, such as Figure 6 As shown, the lower pipe section 102 is located at the end of the central pipe 1. The lower pipe section 102 is directly connected to the upper pipe section 101. The outer diameter of the lower pipe section 102 is small. The annular groove 103 can be set on the outer wall of the connection between the lower pipe section 102 and the upper pipe section 101 to reduce the connection strength and ensure that after the plug 4 slides into the lower pipe section 102, the connection can be cut off, so that the plug 4 and the lower pipe section 102 can be separated from the upper pipe section 101 of the central pipe 1.

[0062] In one embodiment, the inner wall of the central tube 1 is provided with a plurality of circumferentially distributed guide grooves 12, and a first key body 11 is formed between adjacent guide grooves 12. The upper end of the guide groove 12 extends to the upper tube section 101, and the lower end of the guide groove 12 extends to the lower tube section 102, such as... Figure 1 , Figure 2 and Figure 6 As shown, after the plug 4 rotates until the second key 42 aligns with the guide groove 12, the second key 42 can move downwards within the guide groove 12, thereby allowing the plug 4 to move into the lower pipe section 102 and apply pressure to it. The guide groove 12 guides the downward movement of the plug 4. The lower end of the guide groove 12 can be closed, and the second key 42 moves downwards to abut against the lower end of the guide groove 12, thereby applying pressure to the lower pipe section 102 through the lower end of the guide groove 12.

[0063] The first key body 11 can be a strip-shaped protrusion extending axially along the central tube 1. Furthermore, the upper end of the first key body 11 is designed with a bevel to guide it into the guide groove 12. Preferably, there are six first key bodies 11 and six second key bodies 42.

[0064] The elastomer 90 can be an elastic mechanism such as a spring. Preferably, the elastomer 90 is a high-elasticity rubber ball 91, which is a highly elastic spherical soluble rubber. Placed at the bottom of the internal space of the central tube 1, the high-elasticity rubber ball 91 is compressed and deformed when the temporary plug is installed on the surface. After the downhole fracturing operation is completed, the high-elasticity rubber ball 91 rebounds, causing the plugging body 4 to rotate, achieving full borehole clearance. The lower end of the downpipe section 102 has a circular groove inside, into which the high-elasticity rubber ball 91 can be inserted to limit its movement and achieve effective compression of the high-elasticity rubber ball 91.

[0065] The guide structure 73 causes the blockage body 4 to rotate circumferentially when it moves relative to the guide mechanism 7 along the axial direction of the central tube 1. The guide structure 73 guides the circumferential rotation of the blockage body 4. The guide structure 73 can be a spiral surface, groove or protrusion, etc.

[0066] In one embodiment, the guide structure 73 includes a first guide ramp 74, and the plug 4 is provided with a second guide ramp 41 that cooperates with the first guide ramp 74, such as... Figures 2-5 As shown, both the first guide slope 74 and the second guide slope 41 are inclined in the circumferential direction along the axial direction of the central tube 1. After the second guide slope 41 contacts the first guide slope 74, as... Figure 14 As shown, the blockage body 4 continues to move upward, and under the combined action of the second guide slope 41 and the first guide slope 74, the blockage body 4 will rotate simultaneously. The second guide slope 41 and the first guide slope 74 can be curved surfaces or planes.

[0067] Furthermore, the guide structure 73 includes a guide cylinder 71, which is sleeved on the outside of the plugging body 4. A limiting ring 72 is provided on the inner side of the guide cylinder 71, and a first guide inclined surface 74 is provided on the lower side of the limiting ring 72. A second guide inclined surface 41 is provided on the upper side of the second key body 42, and the limiting ring 72 is provided above the second key body 42 and can limit the second key body 42 to the lower side of the limiting ring 72. The inner diameter of the limiting ring 72 is smaller than the outer diameter of the second key body 42, so that the second key body 42 cannot move above the limiting ring 72, thus limiting the movement of the plugging body 4. After the second guide inclined surface 41 of the plugging body 4 contacts the first guide inclined surface 74, it can only move a certain distance and rotate a certain angle, thus restricting the movement range of the plugging body 4. During assembly, it is convenient to insert the guide cylinder 71 and the plugging body 4 together into the central tube 1.

[0068] The guide cylinder 71 is preferably a cylindrical body. The inner diameter of the lower end of the guide cylinder 71 is larger, and the inner diameter of the upper end is smaller, so as to form a limiting ring 72 at the upper end. The lower stepped surface of the limiting ring 72 is provided with a first guide slope 74. Preferably, there are 6 first guide slopes 74. Figures 3-5 As shown, the six first guide slopes 74 are toothed slopes, which cooperate with the second guide slope 41 of the blockage body 4.

[0069] The plug 4 can be cylindrical, with a smaller outer diameter at the upper end and a larger outer diameter at the lower end. A second guide slope 41 is provided on the upper stepped surface of the lower end cylinder. Preferably, there are six second guide slopes 41. Figure 2 As shown, the six second guide slopes 41 are toothed slopes, and each second guide slope 41 is correspondingly provided with a second key body 42. The angle and direction of the upper slope of the second key body 42 are consistent with the angle and direction of the second guide slope 41. The second guide slope 41 engages with the first guide slope 74 of the guide cylinder 71 to achieve the rotation of the blockage body 4. The second key body 42 is used to cooperate with the guide groove 12 at the end of the central tube 1, so that the blockage body 4 slides into the guide groove 12 of the central tube 1 after rotation.

[0070] In one embodiment, the guide cylinder 71 and the blocking body 4 are connected by a shear pin 9, such as Figure 1 and Figure 11As shown, during surface assembly, the guide tube 71 and the plug 4 are connected together by shear pins 9, which facilitates the installation of both into the central tube 1 and the well entry operation; by increasing the fracturing fluid pressure, the shear pins 9 can be cut off, and the plug 4 can then move relative to the guide tube 71.

[0071] Specifically, three threaded holes are evenly distributed on the lower circumference of the guide cylinder 71, and three light holes are also designed on the outer side of the second key body 42 of the plug body 4. The shear pin 9 passes through the threaded hole on the guide cylinder 71 and into the light hole on the plug body 4 to connect and fix the guide cylinder 71 and the plug body 4.

[0072] The inner space of the central tube 1 has a larger inner diameter at the upper end and a smaller inner diameter at the lower end, forming a stepped surface, which facilitates connection with the lower end of the guide tube 71 and provides a fixed support function.

[0073] In one embodiment, the temporary plug further includes a fixing mechanism 3, which is disposed inside the central tube 1 and abuts against the upper end of the guide cylinder 71. The fixing mechanism 3 is threadedly connected to the central tube 1. By rotating the fixing mechanism 3, under the action of the thread, the fixing mechanism 3 can move downward relative to the central tube 1, thereby applying downward pressure to the guide cylinder 71 and the plugging body 4, causing the plugging body 4 to compress the elastic body 90 downward and undergo elastic deformation, thus fixing the guide cylinder 71 and the plugging body 4 inside the central tube 1 for easy insertion into the well.

[0074] like Figure 1 and Figure 7 As shown, the fixing mechanism 3 includes a fixing cylinder 31, which is sleeved on the outside of the plugging body 4. The outer wall of the fixing cylinder 31 is threadedly connected to the inner wall of the central tube 1, so that the plugging body 4 can be driven to move downward by rotating the fixing cylinder 31. Preferably, the top end of the fixing cylinder 31 is designed with two top grooves 32, which can be locked with a wrench to facilitate locking and rotation during the insertion of the fixing cylinder 31 into the central tube 1.

[0075] The fixed cylinder 31 can be a cylindrical body. The fixed cylinder 31 and the central tube 1 are sealed together. Specifically, the lower end of the outer wall of the fixed cylinder 31 is designed with two sealing grooves, which can accommodate O-ring seals 5 to achieve a seal with the central tube 1. The upper end of the central tube 1 has internal threads, and the upper end of the outer wall of the fixed cylinder 31 has external threads for connection with the internal threads at the upper end of the central tube 1, thus locking the internal mechanism of the central tube 1. The fixed cylinder 31 and the plug 4 are also sealed together. Specifically, the upper cylindrical part of the plug 4 has two sealing grooves, which can accommodate O-ring seals 5 to achieve an effective seal with the internal space of the fixed cylinder 31. The upper end of the fixed cylinder 31 has internal threads for connection with the corresponding bridge plug setting adapter.

[0076] The plug 4, guide cylinder 71, fixing cylinder 31, and high-elastic rubber ball 91 can be assembled with the central tube 1 according to the following steps:

[0077] (1) Place the high-elasticity rubber ball 91 into the bottom of the central tube 1;

[0078] (2) Install an O-ring 5 at the groove at the upper end of the plug 4, align the plug 4 with the threaded hole on the guide cylinder 71, and install the fixing shear pin 9 to form a whole;

[0079] (3) Place the connector between the blocker 4 and the guide mechanism 7 into the center tube 1, and align the second key 42 outside the blocker 4 with the first key 11 at the lower end of the center tube 1.

[0080] (4) Install an O-ring 5 in the groove at the upper end of the fixed cylinder 31. Align the lower end of the fixed cylinder 31 with the upper end of the plug 4 inside the central tube 1. The upper end of the fixed cylinder 31 is designed with an external thread. After the fixed cylinder 31 is placed inside the central tube 1, the external thread at the upper end of the fixed cylinder 31 is tightly connected with the internal thread at the upper end of the central tube 1.

[0081] (5) By rotating the fixed cylinder 31, the high-elastic rubber ball 91 is compressed until it rotates to the end of the thread.

[0082] like Figure 6 As shown, the central tube 1 is a tubular structure with a tapered surface at the upper end, which can be used to achieve ball sealing when the temporary plug has not established a seal at the bottom of the well; the upper end is also designed with a stepped surface, which is used to tightly connect the temporary plug with the setting tool during the setting process.

[0083] In one embodiment, the setting mechanism 80 includes an expansion mechanism 2, an anchoring mechanism 8, and a sealing mechanism 6. The outer wall of the expansion mechanism 2 is provided with a conical surface 21. The anchoring mechanism 8 can move upward relative to the expansion mechanism 2, and during the relative upward movement, it can expand outward under the action of the conical surface 21 of the expansion mechanism 2. The sealing mechanism 6 can move upward relative to the expansion mechanism 2, and during the relative upward movement, it can expand outward under the action of the conical surface 21 of the expansion mechanism 2. After the anchoring mechanism 8 expands outward, it can anchor with the external casing or well wall. After the sealing mechanism 6 expands outward, it can seal with the external casing or well wall, thereby completing the setting of the temporary plug.

[0084] like Figure 2 As shown, the upper end of the expansion mechanism 2 is designed as a cylindrical structure, suitable for adapters of corresponding models of setting tools. The conical surface 21 can be set at the lower end of the expansion mechanism 2. The conical surface 21 is designed as an inverted conical structure. When the setting tool is ignited and set, the expansion mechanism 2 moves downward, which can expand the sealing mechanism 6 and the anchoring mechanism 8 to achieve wellbore sealing.

[0085] The sealing mechanism 6 can be designed as a cylindrical structure, made of soluble rubber, with a conical upper end and a cylindrical lower end. The interior is designed as a conical structure, with the angle of the conical inclined surface being the same as the angle of the conical surface 21 of the expansion mechanism 2, which facilitates the expansion of the sealing mechanism 6 during the downward movement of the expansion mechanism 2.

[0086] In one embodiment, the anchoring mechanism 8 is designed as an integral structure, such as... Figure 8 As shown, the design features an eight-lobed slip 81. Between each pair of slips 81, a linear groove is designed with staggered vertical grooves using a wire-cutting method, facilitating the expansion of the anchoring mechanism 8 under the action of the expansion mechanism 2. Each slip 81 has three toothed grooves with three alloy teeth embedded in them, allowing for stable anchoring to the inner wall of the sleeve after expansion by the anchoring mechanism 8.

[0087] like Figure 1 As shown, a locking mechanism 61 can be connected to the outside of the central tube 1. The locking mechanism 61 is designed as a conical structure with eight guide keys on its upper end face. Each slip 81 of the anchoring mechanism 8 has a sliding groove at its lower end. The inclination angle of the guide keys is consistent with the angle direction of the sliding groove at the bottom of the anchoring mechanism 8, which is used to guide the expansion of the anchoring mechanism 8. The lower end of the locking mechanism 61 is designed as an inverted cone shape to facilitate tool insertion and pumping. The upper section 101 of the central tube 1 has an external thread at its end, and the locking mechanism 61 has an internal thread inside, which is used to connect with the external thread at the end of the central tube 1 to lock the temporary sealing plug body.

[0088] During assembly, the expansion mechanism 2, sealing mechanism 6, anchoring mechanism 8, and locking mechanism 61 are sequentially installed onto the central tube 1. The locking mechanism 61 is tightly connected to the end of the central tube 1 to achieve external locking of the temporary seal plug.

[0089] Figure 1 In the temporary sealing plug shown, a high-elasticity rubber ball 91 is placed at the bottom of the central tube 1 and compressed. The internal structure of the central tube 1, from bottom to top, consists of a plug body 4, a guide mechanism 7, and a fixing mechanism 3. The external structure of the central tube 1, from bottom to top, consists of a locking mechanism 61, an anchoring mechanism 8, a sealing mechanism 6, and an expansion mechanism 2. The upper end of the expansion mechanism 2 contacts the upper stepped surface of the central tube 1. The locking mechanism 61 is connected to the end of the central tube 1 via a thread. The ground assembly process of this temporary sealing plug includes:

[0090] (1) First, place the high-elasticity rubber ball 91 into the bottom of the central tube 1; insert the guide tube 71 from the upper end of the plug body 4 until the threaded hole on the plug body 4 is aligned with the threaded hole on the guide tube 71, and then insert the shear pin 9.

[0091] (2) Install two soluble O-rings 5 ​​in the two sealing grooves at the upper end of the plug 4. The plug 4 and the guide cylinder 71 form a whole and are placed into the central tube 1. During the process of placing it into the central tube 1, such as Figure 9 As shown, the second key body 42 at the lower end of the blockage body 4 is aligned with the first key body 11 at the lower end of the central tube 1;

[0092] (3) After installing two soluble O-rings 5 ​​in the two sealing grooves at the lower end of the fixed cylinder 31, the fixed cylinder 31 is placed into the central tube 1.

[0093] (4) Use a wrench to clamp the two top grooves 32 of the upper end of the main fixing cylinder 31, rotate the fixing cylinder 31, the high elastic rubber ball 91 in the central tube 1 is compressed, the fixing cylinder 31 pushes the guide cylinder 71 and the blockage body 4 to move downward until the lower end of the guide cylinder 71 contacts the lower end of the step surface of the central tube 1, and the fixing cylinder 31 can no longer rotate downward.

[0094] (5) After installing the expansion mechanism 2, sealing mechanism 6 and anchoring mechanism 8 on the outside of the central tube 1 in sequence, the locking mechanism 61 is rotated onto the thread at the rear end of the central tube 1 for locking.

[0095] The downhole fracturing process for temporary plugging includes:

[0096] (1) After the temporary sealing plug is pumped into the well to the setting position, the ignition setting is performed. The expansion mechanism 2 moves downward, and the sealing mechanism 6 expands radially under the action of the cone surface 21 of the expansion mechanism 2. The anchoring mechanism 8 expands radially along each linear groove under the action of the expansion mechanism 2. The slip 81 teeth on the anchoring mechanism 8 are anchored on the inner wall of the casing until the internal release thread at the upper end of the central tube 1 is sheared off, thus completing the setting process. After the setting is completed, fracturing operations can be carried out without the need to insert soluble balls.

[0097] (2) During the fracturing operation, pressure is transmitted to the upper end of the plugging body 4 through the fracturing fluid. The guide tube 71 is fixed on the lower step surface of the central tube 1, such as... Figure 11 and Figure 12 As the plugging body 4 moves downward, the shear pin 9 between the plugging body 4 and the guide cylinder 71 is sheared off. The plugging body 4 continues to move downward, and the high-elasticity rubber ball 91 in the central tube 1 is further compressed until the end of the guide key on the plugging body 4 contacts the second key body 42 inside the central tube 1. The pressure is transmitted to the entire central tube 1 through the second key body 42. The central tube 1 transmits the pressure to the expansion mechanism 2, the sealing mechanism 6, the anchoring mechanism 8, and the locking mechanism 61. The overall structural strength is sufficient to support the normal operation of the fracturing operation.

[0098] (3) After fracturing is completed, the wellhead discharge rate decreases, the bottom hole pressure drops rapidly, the high-elasticity rubber ball 91 at the bottom of the central tube 1 rebounds, and the plugging body 4 moves upward under the influence of the rebound force of the high-elasticity rubber ball 91. The second guide slope 41 at the upper end of the plugging body 4 contacts the first guide slope 74 of the guide cylinder 71, and the plugging body 4 rotates. Figure 10 and Figures 13-14As shown, the second key body 42 of the blockage body 4 is aligned with the guide groove 12 between the first key body 11 at the lower end of the central tube 1.

[0099] The process of temporarily sealing and restoring the wellbore access includes: increasing the wellhead flow rate, increasing the bottomhole pressure, and causing the plugging body 4 to slide down through the guide groove 12 at the lower end of the central pipe 1 to the bottom of the central pipe 1 under pressure, with the lower pipe section 102 of the central pipe 1 bearing the pressure; continuing to increase the wellhead flow rate until the connection between the lower pipe section 102 and the upper pipe section 101 of the central pipe 1 is severed, and the lower pipe section 102 and the plugging body 4 slide down to the bottom of the well together, forming a full bore in the wellbore. After the wellbore is fully bore formed, the above operations can be repeated. After installing the tool string on the surface and pumping it into the well, the next stage of fracturing operation can be carried out. The fluid pumped for subsequent construction of the bridge plug and plugging ball will evenly enter all fracturing segments through the central channel, significantly reducing over-displacement of a single segment.

[0100] After the fracturing operation is completed, the plug in the middle of the temporary plug can fall off on its own, realizing full-bore access in the wellbore. During the next stage of fracturing tool insertion and pumping, the risk of sand particles in the fractured cracks being displaced by the pumped fluid due to wellbore blockage and transported to the formation depth is effectively avoided.

[0101] This temporary plug, made of soluble materials, provides a soluble temporary plug for key downhole tools in oil and gas drilling and fracturing. It eliminates the need for ball dropping and delivery during well completion fracturing operations. After fracturing, a secondary pump restart allows the temporary plug to restore the central borehole channel, losing its sealing function. Fluid flow channels are restored above and below the tool, reducing over-displacement of the already treated sections during the subsequent tool string and plugging ball pumping process, improving efficiency, and maximizing reservoir stimulation effectiveness. Furthermore, it saves on fluid delivery and operation time for each treated section.

[0102] The above descriptions are merely a few embodiments of the present invention. Those skilled in the art can make various modifications or variations to the embodiments of the present invention based on the content disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A temporary sealing plug, characterized in that, include: The central tube has a first key body on its inner wall; A setting mechanism, which is installed outside the central tube, is used to achieve setting; A plug is installed inside the central tube. The plug is used to block the flow channel inside the central tube. The plug is provided with a second key body. The second key body can abut against the first key body to prevent the plug from moving downward. A guiding mechanism is provided with a guiding structure, and the blocking body can rotate under the guiding action of the guiding structure when it moves upward relative to the guiding mechanism; An elastomer, which is mounted on the central tube and is used to apply an upward force to the plug; The central tube includes an upper tube section and a lower tube section, and the sealing mechanism is installed on the upper tube section; the upper part of the first key body is disposed on the upper tube section; the blocking body can rotate under the guidance of the guiding structure until the first key body and the second key body are misaligned, and the blocking body can continue to move downward until it abuts against the lower tube section; The guiding structure includes a first guiding inclined surface, and the plug body is provided with a second guiding inclined surface that cooperates with the first guiding inclined surface; the guiding structure includes a guide cylinder, which is sleeved on the outside of the plug body; a limiting ring is provided on the inner side of the guide cylinder, and the first guiding inclined surface is provided on the lower side of the limiting ring; the second guiding inclined surface is provided on the upper side of the second key body, and the limiting ring is provided above the second key body and can limit the second key body to the lower side of the limiting ring; the guide cylinder and the plug body are connected by a shear pin; the temporary sealing plug includes a fixing mechanism, which is provided inside the central tube and abuts against the upper end of the guide cylinder, and the fixing mechanism is threadedly connected to the central tube.

2. The temporary sealing plug according to claim 1, characterized in that, The fixing mechanism includes a fixing cylinder, which is sleeved on the blockage body, and the outer wall of the fixing cylinder is threadedly connected to the inner wall of the central tube.

3. The temporary sealing plug according to claim 1, characterized in that, The outer diameter of the lower pipe section is smaller than the outer diameter of the upper pipe section; And / or, the outer wall of the lower pipe section is provided with an annular groove.

4. The temporary sealing plug according to claim 1, characterized in that, The inner wall of the central tube is provided with a plurality of circumferentially distributed guide grooves, and the first key body is formed between adjacent guide grooves. The upper end of the guide groove extends to the upper pipe section, and the lower end of the guide groove extends to the lower pipe section.

5. The temporary sealing plug according to any one of claims 1-4, characterized in that, The setting mechanism includes an expansion mechanism, an anchoring mechanism, and a sealing mechanism. The outer wall of the expansion mechanism is provided with a conical surface. The anchoring mechanism can move upward relative to the expansion mechanism, and during the upward movement, it can expand outward under the action of the conical surface of the expansion mechanism. The sealing mechanism is capable of moving upward relative to the expansion mechanism, and during the upward movement, it can expand outward under the action of the conical surface of the expansion mechanism.

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